Approach to prevent Shipping/Inventory for bill-only SKUs.

We have 2 phantom items that must be invoiced without creating any Shipping or Inventory activity. Whenever user attempts to choose bill‑only behavior at order entry it works as per expectation (i.e. Lines closed, invoicing interfaced and generated did not generate any inventory/material activity.)
However, lines progress to Schedule/Pick/Ship when they are entered under a Standard Line Type. We want a supported configuration to ensure these SKUs can never initiate shipping or inventory transactions under the standard lines.